Heavy fog blankets the buildings in Beijing, capital of China, Jan. 29, 2013. The National Meteorological Center (NMC) issued a blue-coded alert on Jan. 29 as foggy weather forecast for the coming hours will cut visibility and worsen air pollution in some central and eastern Chinese cities. (Xinhua/Li Mingfang)

Nearly 2,000 passengers were stranded after 20 flights were canceled, an airport official said, adding that heavy fog has blanketed parts of the city of Qingdao since early morning, with visibility reduced to less than 100 meters in some areas. Full story